/* Ppmd8Enc.c -- PPMdI Encoder
   2010-03-12 : Igor Pavlov : Public domain
   This code is based on:
   PPMd var.I (2002): Dmitry Shkarin : Public domain
   Carryless rangecoder (1999): Dmitry Subbotin : Public domain */

#include "Types.h"

#include "Ppmd8.h"

#define kTop (1 << 24)
#define kBot (1 << 15)

void Ppmd8_RangeEnc_FlushData(CPpmd8* p)
{
    unsigned i;
    for (i = 0; i < 4; i++, p->Low <<= 8)
        p->Stream.Out->Write(p->Stream.Out, (Byte)(p->Low >> 24));
}

static void RangeEnc_Normalize(CPpmd8* p)
{
    while ((p->Low ^ (p->Low + p->Range)) < kTop ||
           p->Range < kBot && ((p->Range = (0 - p->Low) & (kBot - 1)), 1))
    {
        p->Stream.Out->Write(p->Stream.Out, (Byte)(p->Low >> 24));
        p->Range <<= 8;
        p->Low <<= 8;
    }
}

static void RangeEnc_Encode(CPpmd8* p, UInt32 start, UInt32 size, UInt32 total)
{
    p->Low += start * (p->Range /= total);
    p->Range *= size;
    RangeEnc_Normalize(p);
}

static void RangeEnc_EncodeBit_0(CPpmd8* p, UInt32 size0)
{
    p->Range >>= 14;
    p->Range *= size0;
    RangeEnc_Normalize(p);
}

static void RangeEnc_EncodeBit_1(CPpmd8* p, UInt32 size0)
{
    p->Low += size0 * (p->Range >>= 14);
    p->Range *= ((1 << 14) - size0);
    RangeEnc_Normalize(p);
}


#define MASK(sym) ((signed char*)charMask)[sym]

void Ppmd8_EncodeSymbol(CPpmd8* p, int symbol)
{
    size_t charMask[256 / sizeof(size_t)];
    if (p->MinContext->NumStats != 0)
    {
        CPpmd_State* s = Ppmd8_GetStats(p, p->MinContext);
        UInt32 sum;
        unsigned i;
        if (s->Symbol == symbol)
        {
            RangeEnc_Encode(p, 0, s->Freq, p->MinContext->SummFreq);
            p->FoundState = s;
            Ppmd8_Update1_0(p);
            return;
        }
        p->PrevSuccess = 0;
        sum = s->Freq;
        i = p->MinContext->NumStats;
        do
        {
            if ((++s)->Symbol == symbol)
            {
                RangeEnc_Encode(p, sum, s->Freq, p->MinContext->SummFreq);
                p->FoundState = s;
                Ppmd8_Update1(p);
                return;
            }
            sum += s->Freq;
        }
        while (--i);

        PPMD_SetAllBitsIn256Bytes(charMask);
        MASK(s->Symbol) = 0;
        i = p->MinContext->NumStats;
        do
        {
            MASK((--s)->Symbol) = 0;
        }
        while (--i);
        RangeEnc_Encode(p, sum, p->MinContext->SummFreq - sum, p->MinContext->SummFreq);
    }
    else
    {
        UInt16* prob = Ppmd8_GetBinSumm(p);
        CPpmd_State* s = Ppmd8Context_OneState(p->MinContext);
        if (s->Symbol == symbol)
        {
            RangeEnc_EncodeBit_0(p, *prob);
            *prob = (UInt16)PPMD_UPDATE_PROB_0(*prob);
            p->FoundState = s;
            Ppmd8_UpdateBin(p);
            return;
        }
        else
        {
            RangeEnc_EncodeBit_1(p, *prob);
            *prob = (UInt16)PPMD_UPDATE_PROB_1(*prob);
            p->InitEsc = PPMD8_kExpEscape[*prob >> 10];
            PPMD_SetAllBitsIn256Bytes(charMask);
            MASK(s->Symbol) = 0;
            p->PrevSuccess = 0;
        }
    }
    for (;;)
    {
        UInt32 escFreq;
        CPpmd_See* see;
        CPpmd_State* s;
        UInt32 sum;
        unsigned i, numMasked = p->MinContext->NumStats;
        do
        {
            p->OrderFall++;
            if (!p->MinContext->Suffix)
                return; /* EndMarker (symbol = -1) */
            p->MinContext = Ppmd8_GetContext(p, p->MinContext->Suffix);
        }
        while (p->MinContext->NumStats == numMasked);

        see = Ppmd8_MakeEscFreq(p, numMasked, &escFreq);
        s = Ppmd8_GetStats(p, p->MinContext);
        sum = 0;
        i = p->MinContext->NumStats + 1;
        do
        {
            int cur = s->Symbol;
            if (cur == symbol)
            {
                UInt32 low = sum;
                CPpmd_State* s1 = s;
                do
                {
                    sum += (s->Freq & (int)(MASK(s->Symbol)));
                    s++;
                }
                while (--i);
                RangeEnc_Encode(p, low, s1->Freq, sum + escFreq);
                Ppmd_See_Update(see);
                p->FoundState = s1;
                Ppmd8_Update2(p);
                return;
            }
            sum += (s->Freq & (int)(MASK(cur)));
            MASK(cur) = 0;
            s++;
        }
        while (--i);

        RangeEnc_Encode(p, sum, escFreq, sum + escFreq);
        see->Summ = (UInt16)(see->Summ + sum + escFreq);
    }
}